Hello Community,
A very common question, perhaps the first question I hear,
Is it possible to extend, split, convert, double, use multiple GX Touch 50's or do anything fancy with the HDMI output of the Cerbo GX?
asked
Can I use HDMI splitters, extension cables, joiners, converters or extenders with the Cerbo GX?
Hi, to add a bit of tech. background, mostly on the splitter function, not so much wrt extending the cable:
The image signals are standard HDMI, and probably works with most splitters.
The touch function in the GX Touch is *not* on the USB cable as some might expect it to be. Instead its also on the HDMI signal. In a proprietary manner: there is no default touch support inside HDMI. Touch consists of two signals: a data line (I2C) and an interrupt line.
The data line of the touch is on one the I2C signals that is part of hdmi. Just as background: all HDMI displays are required to have a eeprom at address 50 containing details about resolution and such. On that same I2C network, we added the touch driver, on a different address. Then there is also a touch interrupt signal, for which we are using another line in the HDMI signal.
On the Linux kernel, we've linked that I2C signals as well touch interrupt into one of the standard linux touch drivers. With some extra fanciness to make it work when plugged in after boot rather than being plugged in when already booted.
The USB cable of the GX touch is *only* used for power. Nothing else. That being said, the Cerbo GX does support a USB keyboard and/or mouse. Note that we don't test or design for that, it just happens to work out of the box. At the moment, and probably remains working.
Conclusion: the only solution we support is to plug the supplied cable direct into the Cerbo GX.
And for the experimental people: try the simplest splitter you can find, the more passive it is, the more chance that touch will work on at least one of the displays. It will most likely never work on multiple; unless someone designs a HDMI splitter to work with the GX Touch.
The only configuration that is thoroughly tested, supported and known to work is the supplied GX Touch cable connected directly to the Cerbo GX.
The touch part on multiple GX Touch displays using some HDMI splitter does not work, and is not supported.
Multiple displays without using touch may work, but is also not supported. If you do manage to get multiple displays to work, USB keyboard connected to the Cerbo GX can allow input.
No idea if multiple keyboards work :)
Also using an HDMI extension cable with a single display is similar. It may work for the display, I will do some more testing with different extension cables to see if touch is reliable and to what length. None should be considered supported.
I tried with 3 different types of HDMI splitters, powered and unpowered, with Systems on Chips and scalers and just dumb ones. Touch did not work at all on some, and was so bad as to be dangerous (mis-hit targets, random delay) on another.
Just the display part (no touch) did work about 95% of the time when split, sometimes one screen was black. Sometimes Cerbo GX rebooted for no obvious reason. So even when working, would not be considered good enough to use.
I have one more very high quality HDMI splitter, studio grade, in use in the studio, that I have not tested yet because it’s all fixed in and doing a job. I will test this too at some point, it may be possible that there is one, or some specific units out there that do work ok
But I definitely saw enough to say the ONLY solution that should be considered supported is the supplied cable direct into the Cerbo GX.
Thank you for the feedback on this. The problem I have is that the web app for the screen is way too slow. Do you plan on integrating the app directly in the Victron android app? If the UI for secondary displays was responsive enough I would have no problem buying a small tablet or phone and using that for the second or third display. There has to be a better option. If you pushed the UI into the Victron mobile app then you wouldn't need to pass a Canvas object and force a browser to do all the logic. I am really bummed out that I can't throw enough money at this problem. Even if I were to buy another Cerbo I couldn't get what I wanted. Any other ideas or recommendations?
By web app, do you mean the remote console on VRM, or http://venus.local ?
I can’t say much for sure regarding additional future options, except that continuous improvement, performance and simplicity are the goals.
VictronConnect is a key part of that vision.
Yes the built in web app. If you didn't use the canvas object for animations and relied on Android/iPhone it would be night and day difference. Cerbo can't really be a all in one until u can provide multiple screens. I sure hope you bring the UI to Android.
In my installation I had to extend both USB and HDMI by about 3 extra meters.
I find that a cheap and simple HDMI female to female adapter works best with a normal HDMI cable instead of HDMI splitter or HDMI extension cable.
Hello, I was hoping to be able to extend the distance from Cerbo to Touch 50 over ethernet and have tried several hdmi extenders. Thanks to Amazon's free return policy. I found one that is overkill on the connections, it supports IR and serial also. But it works, including touch and survives a cerbo reboot. I have the Touch GX powered by a separate power supply and about a 25 ft Cat 5e cable using these extenders: AV Access 4KEX70-L. It is important to get a working HDMI cable from the Cerbo GX to the Av Access transmitter, I had one cable that did not work. There are cheaper versions from AV Access but this one is working for me and I am just going to go with it.
Hey @brainodo, thanks for letting all here know - super.
Could you just add a android tablet to the wifi for a second screen? I had to run an android for 3 months while I waited for the touch to show up. Just connected it to the remote console through a browser. Set it to default to it as a home screen. It worked just fine, except I would have to reconnect every once in a while.
I never tried both at same time after I received the touch 50.
thanks you very for this information, very useful and clear.
i would like to know if you can show the pin out of the HDMI of the Touch Panel, in case a customer would like to make the cable to avoid to lose the touch function.
have a nice day.
Its the standard hdmi pin-out, that should be enough info I hope?
Self making a HDMI cable by the way is quite a challenge, signal frequency is enormously high, and requirements wrt shielding etcetera as well. Its not something I'd recommend to do.
We found a solution for a Cerbo GX and GX Touch extension issue - where is Furuno MFD was installed and asked for a separate GX touch screen independently to monitor Victron equipment installed onboard for 77 feet boat. This is a HDMI - USB 60mt extender which allows touch screens to transfer data via ethernet cables. There are 2 cables located in between the receiver and transmitter separately for screen and information transfer. The transmitter (which is close to Cerbo GX) gets the power supply over USB connection (from Cerbo). But the receiver (which is at the GX touch panel) requires 5,3 V supply (maybe a DC-DC converter can be used).
These cables should be isolated from other cables against interference or parazite.
We haven't tested this system for a long time but on the test bench, it works smoothly.
https://www.youtube.com/watch?v=Nb3icXmI1_4
Hi,
your comment and your video do not say which HDMI extender you used.
Which device is it? (make and model if you can)
thanks
Good morning,
I just got linked to this thread by Bob Hopman.
I think, as the separation of the CPU and the interface panel really suggests large distances and multiple panels, this should be a thing, Victron should address. Maybe in a future device.
We "only" build expedition vehicles, but even there, our design team immediately put the panel in a space, where it's almost 10m cable length away from the Cerbo. And this is just a 7m unit...
Imagine a larger RV or even a boat... you want a command panel in the engine room / tech room, one on the bridge and one in the saloon. Not just monitors, but with full functionality.
What is the reason not to use USB as touch communication? I thought, that is the standard for touch displays... and with USB, you usually can connect several devices like mouse, touchscreen, digitizer...
Cheers
Daniel
